1. Field of the Invention
The present invention relates to an intravascular prosthesis, and more particularly, concerns a percutaneously deliverable prosthesis suitable for the intravascular filtration of blood so that migration of blood clot emboli may be prevented.
2. Description of the Prior Art
Blood vessels of humans or animals undergo a natural degenerative process or are sometimes subject to weakness. In weakened blood vessels, aneurysms may occur. The degenerative effect on blood vessels may also cause a narrowing or constriction of the lumen of the vessel so that blood flow is restricted. In other degenerative situations, or for other reasons, clots or emboli may occur which, should they migrate within the intravascular system, could be very dangerous.
With respect to the aforementioned intravascular problems, surgical intervention has been the primary technique for providing relief. For example, aneurysm repair involves a surgical procedure in which an intraluminal vascular prosthesis is inserted into the damaged vessel to reconstruct the section that needs repair. For clogged blood vessels, the excision of thickened atheromatous areas of the vessel has been performed by an endarterectomy procedure. Vascular filter, such as those placed in the vena cava, presently involves the positioning of a expandable structure or balloon within the vena cava. Such filters have been known to migrate, and are often difficult to properly orient within the vena cava. These and other intravascular therapy procedures of an invasive nature are not only risky, but are also costly.
Angioplasty procedures, using expandable balloons, have been developed for widening the lumen of diseased, constructed blood vessels. Many of these angioplasty procedures are performed percutaneously so that the balloon is introduced into the blood vessel through a catheter inserted through the skin into the vascular system. After the inflation of the expandable balloon widens the clogged blood vessel, it is withdrawn from the blood vessel through the introducer catheter. Balloon catheters are also available in which the inflated balloon is detachable from the catheter once inflated within the blood vessel. The inflated, detached balloon occludes the blood vessel, and is therefore useful in such procedures as varicocele treatment. Such a detachable balloon catheter system, known as the MINIBALLOON.TM. catheter, is sold by Becton, Dickinson and Company, Paramus, N.J.
Although inflatable and detachable balloon catheter procedures, performed percutaneously, are known and available for some intravascular therapy applications, surgery is still relied upon for other applications. Less invasive techniques are being sought for blood vessel repair, reconstruction and filtering, as well as vessel occlusion, blood flow regulation or flow assist. The present invention is directed to a device which provides for minimal invasive methods of intravascular therapy. In particular, the present invention is directed to an intravascular prosthesis, percutaneously deliverable, which is suitable for the filtration of blood clot emboli in the blood and for the reinforcement or reconstruction of weakened blood vessels, as well as aneurysm repair. Two copending patent applications, having a common assignee herewith, Ser. No. 772,216 and Ser. No. 772,217 both filed on Sept. 3, 1985 relate to those intravascular therapy applications involving blood vessel reinforcement without filtering, and to blood vessel occlusion and blood flow regulation.